A Simple explanation of APIs.

API stands for Application Programming Interface. They are mechanisms that enable two software components to communicate with each other using a set of definitions and protocols.

How it works

API architecture is usually explained in terms of client and server. The application sending the request is called the client, and the application sending the response is called the server.

1)  SOAP(Simple Object Access Protocol)
    It uses XML for exchanging messages between client and server.

2) RPC(Remote Procedure Calls)
   Clients completes a function on the server and sends the output back to client.

3) Websocket  
   Uses Json object to pass data 
   Support two-way communication between the client application and server4) .

4) REST(Representational State Transfer)
   Client and server exchange data using HTTP . It is statelessness

Benefits of REST APIs

        ▪ Integration
          They are used to integrate new applications with existing software systems

        ▪ Innovation
          Entire industries can change with the arrival of a new app.

        ▪ Expansion
          It present a unique opportunity for businesses to meet their clients’ needs across different platforms.

        ▪ Ease of maintenance
          It acts as a gateway between two systems. Any future code changes by one party do   not impact the other party.

Types of APIs

Private APIs These are internal to an enterprise and only used for connecting systems and data within the business.

Public APIs These are open to the public and may be used by anyone. There may or not be some authorization and cost associated with these types of APIs.

Partner APIs These are only accessible by authorized external developers to aid business-to-business partnerships.

Composite APIs These combine two or more different APIs to address complex system requirements or behaviors.

What is an API endpoint and why is it important?

Endpoints are the final touchpoints in the API communication system. These include server URLs, services, and other specific digital locations from where information is sent and received between systems. API endpoints are critical to enterprises for two main reasons:

Security API endpoints make the system vulnerable to attack. API monitoring is crucial for preventing misuse.
Performance API endpoints, especially high traffic ones, can cause bottlenecks and affect system performance.

How to secure a REST API?

Authentication tokens These are used to authorize users to make the API call. Authentication tokens check that the users are who they claim to be and that they have access rights for that particular API call. For example, when you log in to your email server, your email client uses authentication tokens
API keys API keys verify the program or application making the API call. They identify the application and ensure it has the access rights required to make the particular API call. API keys are not as secure as tokens but they allow API monitoring in order to gather data on usage. You may have noticed a long string of characters and numbers in your browser URL when you visit different websites. This string is an API key the website uses to make internal API calls.

How to use an API?

The steps to implement a new API include:

1. Obtaining an API key. This is done by creating a verified account with the API provider.
2. Set up an HTTP API client. This tool allows you to structure API requests easily using the API keys received.
3. If you don’t have an API client, you can try to structure the request yourself in your browser by referring to the API documentation.
4. Once you are comfortable with the new API syntax, you can start using it in your code.

Where can I find new APIs?

New web APIs can be found on API marketplaces and API directories. API marketplaces are open platforms where anyone can list an API for sale. API directories are controlled repositories regulated by the directory owner. Expert API designers may assess and test a new API before adding it to their directory.

Some popular API websites include: Rapid API – The largest global API market with over 10,000 public APIs and 1 million active developers on site. Rapid API allows users to test APIs directly on the platform before committing to purchase.

  Public APIs – The platform groups remote APIs into 40 niche categories, making it easier to browse and find the right one to meet your needs.

  APIForThat and APIList – Both these websites have lists of 500+ web APIs, along with in-depth information on how to use them.

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